drivers/usb/core/buffer.c

   1 /*
   2  * DMA memory management for framework level HCD code (hc_driver)
   3  *
   4  * This implementation plugs in through generic "usb_bus" level methods,
   5  * and should work with all USB controllers, regardless of bus type.
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <linux/device.h>
  12 #include <linux/mm.h>
  13 #include <linux/io.h>
  14 #include <linux/dma-mapping.h>
  15 #include <linux/dmapool.h>
  16 #include <linux/usb.h>
  17 #include <linux/usb/hcd.h>
  18
  19
  20 /*
  21  * DMA-Coherent Buffers
  22  */
  23
  24 /* FIXME tune these based on pool statistics ... */
  25 static size_t pool_max[HCD_BUFFER_POOLS] = {
  26         32, 128, 512, 2048,
  27 };
  28
  29 void __init usb_init_pool_max(void)
  30 {
  31         /*
  32          * The pool_max values must never be smaller than
  33          * ARCH_KMALLOC_MINALIGN.
  34          */
  35         if (ARCH_KMALLOC_MINALIGN <= 32)
  36                 ;                       /* Original value is okay */
  37         else if (ARCH_KMALLOC_MINALIGN <= 64)
  38                 pool_max[0] = 64;
  39         else if (ARCH_KMALLOC_MINALIGN <= 128)
  40                 pool_max[0] = 0;        /* Don't use this pool */
  41         else
  42                 BUILD_BUG();            /* We don't allow this */
  43 }
  44
  45 /* SETUP primitives */
  46
  47 /**
  48  * hcd_buffer_create - initialize buffer pools
  49  * @hcd: the bus whose buffer pools are to be initialized
  50  * Context: !in_interrupt()
  51  *
  52  * Call this as part of initializing a host controller that uses the dma
  53  * memory allocators.  It initializes some pools of dma-coherent memory that
  54  * will be shared by all drivers using that controller.
  55  *
  56  * Call hcd_buffer_destroy() to clean up after using those pools.
  57  *
  58  * Return: 0 if successful. A negative errno value otherwise.
  59  */
  60 int hcd_buffer_create(struct usb_hcd *hcd)
  61 {
  62         char            name[16];
  63         int             i, size;
  64
  65         if (!IS_ENABLED(CONFIG_HAS_DMA) ||
  66             (!hcd->self.controller->dma_mask &&
  67              !(hcd->driver->flags & HCD_LOCAL_MEM)))
  68                 return 0;
  69
  70         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
  71                 size = pool_max[i];
  72                 if (!size)
  73                         continue;
  74                 snprintf(name, sizeof(name), "buffer-%d", size);
  75                 hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
  76                                 size, size, 0);
  77                 if (!hcd->pool[i]) {
  78                         hcd_buffer_destroy(hcd);
  79                         return -ENOMEM;
  80                 }
  81         }
  82         return 0;
  83 }
  84
  85
  86 /**
  87  * hcd_buffer_destroy - deallocate buffer pools
  88  * @hcd: the bus whose buffer pools are to be destroyed
  89  * Context: !in_interrupt()
  90  *
  91  * This frees the buffer pools created by hcd_buffer_create().
  92  */
  93 void hcd_buffer_destroy(struct usb_hcd *hcd)
  94 {
  95         int i;
  96
  97         if (!IS_ENABLED(CONFIG_HAS_DMA))
  98                 return;
  99
 100         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 101                 struct dma_pool *pool = hcd->pool[i];
 102
 103                 if (pool) {
 104                         dma_pool_destroy(pool);
 105                         hcd->pool[i] = NULL;
 106                 }
 107         }
 108 }
 109
 110
 111 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
 112  * better sharing and to leverage mm/slab.c intelligence.
 113  */
 114
 115 void *hcd_buffer_alloc(
 116         struct usb_bus          *bus,
 117         size_t                  size,
 118         gfp_t                   mem_flags,
 119         dma_addr_t              *dma
 120 )
 121 {
 122         struct usb_hcd          *hcd = bus_to_hcd(bus);
 123         int                     i;
 124
 125         if (size == 0)
 126                 return NULL;
 127
 128         /* some USB hosts just use PIO */
 129         if (!IS_ENABLED(CONFIG_HAS_DMA) ||
 130             (!bus->controller->dma_mask &&
 131              !(hcd->driver->flags & HCD_LOCAL_MEM))) {
 132                 *dma = ~(dma_addr_t) 0;
 133                 return kmalloc(size, mem_flags);
 134         }
 135
 136         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 137                 if (size <= pool_max[i])
 138                         return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
 139         }
 140         return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
 141 }
 142
 143 void hcd_buffer_free(
 144         struct usb_bus          *bus,
 145         size_t                  size,
 146         void                    *addr,
 147         dma_addr_t              dma
 148 )
 149 {
 150         struct usb_hcd          *hcd = bus_to_hcd(bus);
 151         int                     i;
 152
 153         if (!addr)
 154                 return;
 155
 156         if (!IS_ENABLED(CONFIG_HAS_DMA) ||
 157             (!bus->controller->dma_mask &&
 158              !(hcd->driver->flags & HCD_LOCAL_MEM))) {
 159                 kfree(addr);
 160                 return;
 161         }
 162
 163         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 164                 if (size <= pool_max[i]) {
 165                         dma_pool_free(hcd->pool[i], addr, dma);
 166                         return;
 167                 }
 168         }
 169         dma_free_coherent(hcd->self.controller, size, addr, dma);
 170 }